Production of selenium compounds

ABSTRACT

A PROCESS FOR THE PRODUCTION OF ACYCLOHEXANONESELENOSEMICARBAZONE BY REACTING AN ALKALI-METAL SELENOCYANATE WITH A HYDRAZINE AND A CYCLOHEXANONE IS DISCLOSED.

United States Patent 3,824,282 PRODUCTION OF SELENIUM COMPOUNDS Douglas James Fry and Patrick Joseph Keogh, Ilford, England, assignors to Ilford Limited, Essex, England No Drawing. Filed Sept. 22, 1971, Ser. No. 182,837 Claims priority, application Great Britain, Sept. 30, 1970, 46,528/70 Int. 'Cl. C07c 163/00 US. Cl. 260--551 R 5 Claims ABSTRACT OF THE DISCLOSURE A process for the production of a cyclohexanoneselenosemicarbazone by reacting an alkali-metal selenocyanate with a hydrazine and a cyclohexanone is disclosed.

The present invention relates to a process for the production of a cyclohexanoneselenosemicarbazone of the general formula I:

where A represents a cyclohexanone and R is a hydrogen atom, a lower alkyl group or an aralkyl group, which comprises reacting an alkali-metal selenocyanate with a hydrazine of the general formula H:

NHz-NH wherein R has the meaning assigned to it above and with a cyclohexanone in the presence of a water-containing inert organic solvent at a temperature above 20 C. and at an initial pH of the reaction mixture ranging from 0.5 to 5.5 at 25 C., and separating the cyclohexanoneselenosemicarbazone formed from the reaction mixture.

By lower alkyl group is meant an alkyl group con taining from 1 to 6 carbon atoms.

By a cyclohexanone is meant cyclohexanone itself or a cyclohexanone which carries one or more substituent groups, for example a methyl group.

It is to be understood that hydrazine hydrate, a free hydrazine or a hydrazine in the form of its acid salt for example hydrazine sulphate may be used in the process of the present invention. Since the use of hydrazine hydrate or a free hydrazine will result in an initial pH of greater than 5.5 and the use of an acid salt for example hydrazine dihydrochloride will result in an initial pH of less than 0.5, it is necessary in order to obtain a mixture having the required initial pH either.

(a) to use hydrazine hydrate or a free hydrazine and add a mineral acid such as hydrochloric acid,

(b) to use a mixture of hydrazine hydrate or a free hydrazine and a mineral acid salt of the hydrazine for example hydrazine sulphate, N H H SO (c) to use a mineral acid salt of a hydrazine for example hydrazine dihydrochloride N H -2HCl, and add an inorganic base such as sodium hydroxide or an inert organic base such as triethylamine.

The pH values mentioned herein are determined from the readings obtained on a pH meter when a Radiometer pH glass electrode Type G202C (made by Radiometer A/S of Copenhagen, Denmark) and a reservoir-fed saturated calomel reference electrode are immersed in the reaction mixture at 25 C. (or as set forth in the Examples), the meter having been previously set to read 4.008 when the same electrodes are immersed in an aqueous 0.05M potassium hydrogen phthalate solution at 25 C.

3,824,282 Patented July 16, 1974 The term initial pH is used because the pH rises during the course of the reaction.

As alkali-metal sodium and preferably potassium are used.

Preferably the process of the present invention is carried out at a temperature ranging from 20 to C., since the yield of the cyclohexanoneselenosemicarbazone is reduced if the temperature exceeds 120 C.

Preferably in the process of the present invention there is an excess of the hydrazine and/or the cyclohexanone in relation to the alkali metal selenocyanate present.

The cyclohexanoneselenosemicarbazones are of use in the production of selenosemicarbazides, usable as photographic bleach-fix accelerators, as described in our copending U.S. application No. 182,838 (corresponding to British application No. 46,526/70), filed on even date herewith.

The preferred water-containing inert organic solvent for use in the process of the present invention is aqueous ethanol.

EXAMPLE I The following are added in order as stated to a mixture of 400 ml. ethanol and 50 ml. water: 5.5 g. hydrazine hydrate (0.11 mol), 8.6 ml. concentrated hydrochloric acid (S.G. 1.18) (0.1 mol), a solution of 14.4 g. potassium selenocyanate (0.1 mol) in .50 ml. water and finally 11.6 g. cyclohexanone (0.12 mol). The pH of the mixture is approximately 2.7 at 26 C. The mixture is boiled under reflux for 2 hours and filtered hot from the deposited selenium (1.3 g.). The filtrate is evaporated under reduced pressure until the distillate consists mainly of water. The resulting mixture is then cooled and the solid product collected by filtration, washed with a little cold ethanol and then with a little ether and dried. The crude product is purified by dissolving: in ml. of boiling chloroform and the insoluble impurities removed by filtration. The chloroform filtrate is evaporated to dryness to yield 9.3 g. of purified cyclohexanoneselenosemicarbazone. Recrystallisation from benzene aifords colourless crystals m.pt. 158 C.

of 400 ml. ethanol and 50 ml. water: 15.5 g. hydrazine hydrate (0.31 mol), 26 ml. concentrated hydrochloric acid (S.G. 1.18) a solution of 14.4 g. potassium selenocyanate (0.1 mol) in-50 ml. water and finally 11.6 ml. cyclohexanone (0.11 mol). The initial pH of the mixture is approximately 3 at 25 C. The mixture is boiled under reflux for 2 hours, filtered hot from the deposited selenium (1.05 g.) and the filtrate evaporated under reduced pressure until the distillate consists mainly of water. The resulting mixture is then cooled and the solid product collected by filtration, washed with a little cold ethanol and then with a little ether and dried. Crude yield 10.58 g The crude product is purified by dissolving in 150 ml. boiling chloroform and the insoluble impurities are removed by filtration. The chloroform filtrate is evaporated to dryness to yield 9.6 g. purified cyclohexanoneselenosemicarbazone. The LR. spectrum of the product is identical to that of cyclohexanoneselenosemicarbazone.

EXAMPLE III The following are added in order as stated to a mixture of 400 ml. ethanol and 50 ml. water: 15.5 g. hydrazine hydrate (0.31 mol), 20 ml. concentrated hydrochloric acid (S.G. 1.18) a solution of 14.4 g. potassium selenocyanate (0.1 mol) in 50 ml. water and finally 30 g. cyclohexanone (0.305 mol). The initial pH of the mixture is approximately 3.4 at 25 C. The mixture is boiled under reflux for 2 hours, filtered hot from the deposited selenium (0.73 g.) and the filtrate evaporated under reduced pressure until the distillate consists mainly of water. The resulting mixture is then cooled and the solid product collected by filtration, washed with a little cold ethanol and then with a little ether and dried. The crude product is purified by dissolving in 150 ml. boiling chloroform and the filtrate is evaporated by dryness to yield 10.66 g. purified. The IR. cyclohexanoneselenosemicarbazone. The I.R. spectrum of the product is identical to that of cyclohexanoneselenosemicarbazone.

EXAMPLE IV The following are added in order as stated to a mixture of 750 ml. ethanol and 50 ml. Water: 46.5 g. hydrazine hydrate (0.93 mol), 75 ml. concentrated hydrochloric acid (S.G. 1.18), a solution of 43.2 g. potassium selenocyanate (0.3 mol) in 50 ml. water and finally 90 g. cyclohexanone (0.92 mol.). The initial pH of the mixture is approximately 2.3 at 40 C. The mixture is boiled under reflux for 35 minutes, filtered hot from the deposited selenium (2.6 g.) and the filtrate evaporated under reduced pressure until the distillate consists mainly of water. The resulting mixture is then cooled and the solid product collected by filtration, washed with a little cold ethanol, a little ether and then dried. Crude yield 40.9 g. The crude product is purified by dissolving in 200 ml. boiling chloroform and the insoluble impurities are removed by filtration. The chloroform filtrate is evaporated to dryness to yield 39.2 g. purified cyclohexanoneselenosemicarbazone. The LR. spectrum of the product is identical to that of cyclohexanoneselenosemicarbazone.

EXAMPLE V To a mixture of 750 ml. ethanol and 50 ml. water are added in order: 46.5 g. hydrazine hydrate (0.93 mol), 48 ml. concentrated hydrochloric acid (S.G. 1.18), a solution of 43.2 g. potassium selenocyanate (0.3 mol) in 50 ml. water and finally 90 g. cyclohexanone (0.92 mol). The initial pH of the mixture is approximately 4.1 at 25 C. The mixture is boiled under reflux for 3.5 hours, filtered hot from the deposited selenium (2.5 g.) and the filtrate evaporated under reduced pressure until all the ethanol has been removed. The residual mixture (about 100 ml.) is cooled and the impure solid cyclohexanoneselenosemicarbazone separated by filtration from the aqueous mother liquors. After washing the impure selenosemicarbazone with a little cold ethanol and then ether, it is purified by dissolving in 400 ml. boiling chloroform and the insoluble impurities are removed by filtration. The chloroform filtrate is evaporated to dryness to yield 18.5 g. purified cyclohexanoneselenosemicarbazone. The I.R. spectrum of the product is identical to that of cyclohexanoneselenosemicarbazone.

The aqueous mother liquors are evaporated under reduced pressure to remove all volatile materials. The residue is caused to crystallise by stirring with 50 ml. n-butanol and the crystals are collected by filtration. The crystals are then lixivated successively with 10 ml. water, 5 ml. water, twice with ml. ethanol and finally with 10 ml. ether and then are recrystallised from ethanol to yield 4.2 g. selenosemicarbazide m.pt. 182 C.

EXAMPLE VI The following are added in order as stated to a mix ture of 400 ml. ethanol and 50 ml. water: 15.5 g. hydrazine hydrate (0.31 mol), ml. concentrated hydrochloric acid (S.G. 1.18), a solution of 14.4 g. potassium selenocyanate (0.1 mol) in 50 ml. water and finally 35 g. 3-methylcyclohexanone (0.31 mol). The initial pH of the mixture is approximately 3. The mixture is boiled under reflux for 2 hours, filtered hot from the deposited selenium (1.15 g.) and the filtrate evaporated under reduced pressure almost to dryness. The residue is boiled with 400 ml. chloroform and the solution so obtained is filtered through a phase separating filter paper. The chloroform. filtrate is evaporated under reduced pressure to dryness and the reddish-brown residue scratched with ether and seeded with 3-methylcyclohexanone-selenosemicarbazone (made from selenosemicarbazide and 3-rnethylcyclohexanone) whereupon the product slowly crystallises and after standing for two hours 3.0 g. coloured crystals are collected by filtration. Recrystallisation from carbon tetrachloride affords colourless crystals m.pt. 118 C. The IR. spectrum of the product is identical to that of cyclohexanoneselenosemicarbazone.

EXAMPLE VII The following are added in order as stated to a mixture of 400 ml. ethanol and 50 ml. water: 43.2 g. methylhydrazine sulphate, 30 g. cyclohexanone, 28.4 ml. 40% w./v. aqueous sodium hydroxide solution and finally 14.4 g. potassium selenocyanate. The initial pH of the mixture is 3. The mixture is boiled under reflux for 2 /2 hours, filtered hot from the deposited selenium and the filtrate evaporated under reduced pressure until the ethanol has been removed. The precipitated solid is collected by filtra tion, washed with water and spirit and then dissolved in 300 ml. hot chloroform, filtered and the chloroform filtrate evaporated under reduced pressure to dryness to give 17 g. of cyclohexanone Z-methyl selenosemicarbazone, m.pt. 180182 C. The LR. spectrum of the product is identical to that of the product of reaction of cyclohex anone with a well characterised sample of Z-methylselenosemicarbazide.

EXAMPLE VIII The following are added in order as stated to a mixture of 750 ml. ethanol and 50 ml. water: 46.5 g. hydrazine hydrate (0.93 mol), ml. concentrated hydrochloric acid (S.G. 1.18), a solution of 43.2 g. potassium selenocyanate (0.3 mol) in 50 ml. water and finally 90 g. cyclohexanone (0.92 mol). The initial pH of the mixture is 1 at 28 C. The mixture is boiled under reflux for 35 minutes, filtered hot from the deposited selenium (6.7 g.), and the filtrate evaporated under reduced pressure until the distillate consists mainly of water. The resulting mixture is then cooled and the solid product collected by filtration, washed with a little cold ethanol, a little ether and then dried. Crude yield 29.1 g. The crude product is purified by dissolving in 200 ml. boiling chloroform and the insoluble impurities are removed by filtration. The chloroform filtrate is evaporated to dryness to yield 29 g. purified cyclohexanoneselenosemicarbazone. The I.R. spectrum of the product is identical to that of cyclohexanoneselenosemicarbazone.

What we claim is:

1. A process for the production of a selenosemicarbazone of the formula:

wherein A represents cyclohexylidene or methylcyclohexylidene and R is a hydrogen atom, a lower alkyl group or an aralkyl group, which comprises reacting an alkali-metal selenocyanate with a hydrazine compound of the formula:

wherein R has the meaning assigned to it above, and with cyclohexanone or methyl cyclohexanone in the presence of a Water-containing inert organic solvent at a temperature above 20 C. and at an initial pH of the reaction mixture ranging from 0.5 to 5.5 at 25 C., said pH being adjusted by (a) adding a mineral acid to the composition, (b) using a mixture of the free hydrazine and a mineral acid salt of the hydrazine, or (c) by using a mineral acid salt of the hydrazine and adding an inorganic base or an inert organic base thereto and separating the selenosernicarbazone formed from the reaction mixture.

2. A process according to claim 1 wherein the process is carried out at a temperature ranging from 20 to 120 C.

3. A process according to claim 2 wherein in the process there is an excess of the hydrazine compound and/or the cyclohexanone compound in relation to the alkali metal selenocyanate used.

4. A process according to claim 3 wherein the watercontaining inert organic solvent is aqueous ethanol.

5. A process according to claim 1 wherein the cyclohexanone compound in cyclohexanone.

5 HARRY I. MOATZ, Primary Examiner US. Cl. X.R. 

